Modeling of experimental acute bronchopneumonia with pulmonary fibrosis

Abstract

. There is currently an urgent need to create an available experimental model to reproduce the main pathogenetic mechanisms of COVID-associated lung injury. Aim – development of the acute bronchopneumonia experimental model with the pulmonary fibrosis. A group of laboratory Wistar rats (n=20) with full observance of bioethical norms under thiopental anesthesia underwent surgery with the introduction into the trachea of sterile nylon thread 2.5 cm long and 0.2 mm thick to a depth of 2.5 cm; in the control group included 5 animals. For 28 days, the animals were observed and performed pathomorphological, cytological, hematological and microscopic examinations. During the observation, the cyanosis increased, breathing became difficult with the active involvement of the respiratory muscles, severe rales and crepitation were heard. Rectal temperature increased by 1–1.5 o C. On sectional examination after 7 days, the lungs were swollen, pale pink in color, had layers of fibrin, severe cyanosis, intra-tissue hemorrhage. After 21 days, these changes were supplemented by the development of atelectasis and fibrosis. On the 21st day, the granulocyte-lymphocyte index increased (1.5 times; p=0.003). Microscopic examination showed the development in the first week of acute exudative bronchopulmonary inflammation, in the second – the formation of peribronchial and alveolar abscesses, with their organization in the third week, with the subsequent development of diffuse parenchymal fibrosis and vascular hyalinosis. The model of acute aspiration bronchopneumonia in rats with the introduction of nylon thread into the trachea allows to obtain the main clinical and morphological manifestations of acute exudative-proliferative damage to the lungs with the development of pulmonary fibrosis.